JP5926590B2 - Manufacturing method of connecting body and connecting method of electronic component - Google Patents

Description

  The present invention relates to a method for manufacturing a connection body in which electronic components and the like are connected using a photocurable adhesive, and a connection method for connecting electronic components and the like using a photocurable adhesive.

  Conventionally, a liquid crystal display device has been widely used as various display means such as a television, a PC monitor, a mobile phone, a portable game machine, a tablet PC, or an in-vehicle monitor. In recent years, in such liquid crystal display devices, so-called COG (chip on glass) in which a liquid crystal driving IC is directly mounted on a substrate of a liquid crystal display panel or a liquid crystal driving circuit from the viewpoints of fine pitch, light weight, and thinning. A so-called FOG (film on glass) that directly mounts the flexible substrate on which the substrate is formed on the substrate of the liquid crystal display panel is employed.

  For example, as shown in FIG. 11, a liquid crystal display device 100 employing a COG mounting system has a liquid crystal display panel 104 that performs a main function for liquid crystal display. The liquid crystal display panel 104 is a glass substrate or the like. And two transparent substrates 102 and 103 facing each other. In the liquid crystal display panel 104, the transparent substrates 102 and 103 are bonded to each other by a frame-shaped seal 105, and the liquid crystal 106 is sealed in a space surrounded by the transparent substrates 102 and 103 and the seal 105. A panel display unit 107 is provided.

  The transparent substrates 102 and 103 have a pair of striped transparent electrodes 108 and 109 made of ITO (indium tin oxide) or the like on both inner surfaces facing each other so as to intersect each other. The transparent substrates 102 and 103 are configured such that a pixel as a minimum unit of liquid crystal display is constituted by the intersection of the transparent electrodes 108 and 109.

  Of the two transparent substrates 102 and 103, one transparent substrate 103 is formed to have a larger planar dimension than the other transparent substrate 102, and the transparent electrode 109 is formed on the edge 103a of the transparent substrate 103 formed to be large. Terminal portion 109a is formed. Further, alignment films 111 and 112 subjected to a predetermined rubbing process are formed on both transparent electrodes 108 and 109, and the initial alignment of liquid crystal molecules is regulated by the alignment films 111 and 112. ing. Further, a pair of polarizing plates 118 and 119 are disposed outside the transparent electrodes 108 and 109, and the vibration direction of transmitted light from the light source 120 such as a backlight is regulated by the polarizing plates 118 and 119. It has come to be.

  On the terminal portion 109a, a liquid crystal driving IC 115 is thermocompression bonded via an anisotropic conductive film 114. The anisotropic conductive film 114 is a film formed by mixing conductive particles in a thermosetting binder resin, and heat conduction is performed between the two conductors so that the electrical conduction between the conductors is achieved by the conductive particles. And the mechanical connection between the conductors is maintained by the binder resin. The liquid crystal driving IC 115 can perform predetermined liquid crystal display by selectively changing the alignment of the liquid crystal by selectively applying a liquid crystal driving voltage to the pixels. In addition, as the adhesive constituting the anisotropic conductive film 114, the most reliable thermosetting adhesive is usually used.

  When the liquid crystal driving IC 115 is connected to the terminal portion 109a through such an anisotropic conductive film 114, first, the anisotropic conductive film 114 is attached to the terminal portion 109a of the transparent electrode 109 by a temporary crimping means (not shown). Temporarily crimp. Subsequently, after the liquid crystal driving IC 115 is mounted on the anisotropic conductive film 114, the liquid crystal driving IC 115 is connected to the terminal together with the anisotropic conductive film 114 by the thermocompression bonding means 121 such as a thermocompression bonding head as shown in FIG. The thermocompression bonding means 121 is caused to generate heat while being pressed toward the portion 109a. Due to the heat generated by the thermocompression bonding means 121, the anisotropic conductive film 114 undergoes a thermosetting reaction, whereby the liquid crystal driving IC 115 is bonded onto the terminal portion 109a via the anisotropic conductive film 114.

  However, in such a connection method using an anisotropic conductive film, the heat pressing temperature is high, and the thermal shock to the electronic components such as the liquid crystal driving IC 115 and the transparent substrate 103 is increased.

  Therefore, a connection method using an ultraviolet curable adhesive instead of the anisotropic conductive film 114 using such a thermosetting adhesive has been proposed. In the connection method using the ultraviolet curable adhesive, the adhesive softens and flows due to heat, and the temperature is high enough to sandwich the conductive particles between the terminal portion 109a of the transparent electrode 109 and the electrode of the liquid crystal driving IC 115. Stop heating and cure the adhesive by UV irradiation.

  However, even in such a connection method using an ultraviolet curable adhesive, the adhesive shrinks as it is cured by ultraviolet irradiation. Therefore, due to the shrinkage, the IC connection portion of the transparent substrate 103 that sandwiches the liquid crystal 106 is warped, so that the surface uniformity of the gap between the transparent substrates 102 and 103 in the panel display portion 107 is lost. The orientation of the liquid crystal is disturbed, and there is a risk of causing problems such as display unevenness. Further, there is a risk of causing a connection failure of the liquid crystal driving IC 115 due to the warp generated in the IC connection portion of the transparent substrate 103.

WO00 / 46315 publication

  Therefore, the present invention solves the above-described problems, and uses an ultraviolet curable adhesive to connect electronic components at a low temperature, and suppresses distortion due to curing shrinkage of the adhesive, thereby connecting the electronic components. It is an object of the present invention to provide a method for manufacturing a connection body that improves defects and a method for connecting electronic components.

In order to solve the above-described problems, a method for manufacturing a connection body according to the present invention includes a step of placing an electronic component on a substrate via a photocurable adhesive, and the adhesive includes a plurality of light sources. A step of irradiating and curing the light, and a region where the substrate and the electronic component are connected is divided into a plurality of connection regions, and the connection regions divided into a plurality are arranged in parallel so as to be adjacent to each other. For each of the connection regions, the corresponding light source is individually controlled to be cured by shifting the timing of the light irradiation start.

The electronic component connecting method according to the present invention includes a step of placing an electronic component on a substrate via a photocurable adhesive, and the adhesive is cured by irradiating light from a plurality of light sources . A region where the substrate and the electronic component are connected is divided into a plurality of connection regions, and the connection regions divided into a plurality are arranged in parallel so as to be adjacent to each other, and for each connection region, The corresponding light sources are individually controlled to be irradiated, and are cured by shifting the timing of the light irradiation start for each connection region.

  According to the present invention, by shifting the timing of light irradiation, the timing of the start of curing is different for each connection region, and the connection between the electronic component and the substrate is attempted while absorbing the distortion due to the curing shrinkage in each connection region. be able to.

It is sectional drawing which shows the mounting process to which this invention was applied. It is sectional drawing which shows an anisotropic conductive film. It is a perspective view which shows the connection area | region formed by connecting an electronic component and a glass substrate. It is a top view which shows the start timing of the ultraviolet irradiation to which this invention was applied. It is a top view which shows other embodiment of this invention. It is a top view which shows other embodiment of this invention. It is a top view which shows other embodiment of this invention. It is a top view which shows other embodiment of this invention. It is a figure for demonstrating the measuring method of the curvature of the glass substrate which concerns on an Example and a comparative example. It is a figure for demonstrating the measuring method of the conduction resistance which concerns on an Example and a comparative example. It is sectional drawing which shows the conventional liquid crystal display panel. It is sectional drawing which shows the COG mounting process of the conventional liquid crystal display panel.

  Hereinafter, a manufacturing method and a connecting method of a connection body to which the present invention is applied will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the present invention. Further, the drawings are schematic, and the ratio of each dimension may be different from the actual one. Specific dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  In the following, a case where an electronic component is connected to a substrate as an object to be connected and an object to be connected will be described as an example. However, the present technology can be applied to other than the connection between the substrate and the electronic component. For example, so-called COG (chip on glass) mounting is performed in which an IC chip for driving a liquid crystal is mounted on a glass substrate of a liquid crystal display panel. As shown in FIG. 1, the liquid crystal display panel 10 includes two transparent substrates 11 and 12 made of a glass substrate and the like, and the transparent substrates 11 and 12 are bonded to each other by a frame-shaped seal 13. . In the liquid crystal display panel 10, the liquid crystal 14 is sealed in a space surrounded by the transparent substrates 11 and 12 to form a panel display unit 15.

  The transparent substrates 11 and 12 have a pair of striped transparent electrodes 16 and 17 made of ITO (indium tin oxide) or the like on both inner surfaces facing each other so as to intersect each other. The transparent electrodes 16 and 17 are configured such that a pixel as a minimum unit of liquid crystal display is configured by the intersection of the transparent electrodes 16 and 17.

  Of the transparent substrates 11 and 12, one transparent substrate 12 is formed to have a larger planar dimension than the other transparent substrate 11, and a liquid crystal driving edge is formed on the edge 12a of the formed transparent substrate 12. A COG mounting unit 20 on which an electronic component 18 such as an IC is mounted is provided, and an FOG mounting unit 22 on which a flexible substrate 21 on which a liquid crystal driving circuit is formed is mounted near the outside of the COG mounting unit 20. ing.

  Note that the liquid crystal driving IC and the liquid crystal driving circuit can perform predetermined liquid crystal display by selectively changing the alignment of the liquid crystal by selectively applying the liquid crystal driving voltage to the pixels. ing.

  In each of the mounting portions 20 and 22, a terminal portion 17a of the transparent electrode 17 is formed. On the terminal portion 17a, an electronic component 18 such as a liquid crystal driving IC and a flexible substrate 21 are connected using the anisotropic conductive film 1 as a conductive adhesive. The anisotropic conductive film 1 contains the conductive particles 4, and conducts the electrode of the electronic component 18 or the flexible substrate 21 and the terminal portion 17 a of the transparent electrode 17 formed on the edge portion 12 a of the transparent substrate 12. Electrically connected through the conductive particles 4. The anisotropic conductive film 1 is an ultraviolet curable adhesive and is fluidized by being thermocompression-bonded by a heating and pressing head 30 described later, whereby the conductive particles 4 are converted into the terminal portions 17a, the electronic component 18, and the flexible substrate 21. By being crushed between each of the electrodes and being irradiated with ultraviolet rays by the ultraviolet irradiator 31, the conductive particles 4 are cured in a crushed state. Thereby, the anisotropic conductive film 1 electrically and mechanically connects the transparent substrate 12 to the electronic component 18 and the flexible substrate 21.

  Further, an alignment film 24 subjected to a predetermined rubbing process is formed on both the transparent electrodes 16 and 17, and the initial alignment of liquid crystal molecules is regulated by the alignment film 24. In addition, a pair of polarizing plates 25 and 26 are disposed outside the transparent substrates 11 and 12, and these polarizing plates 25 and 26 allow transmitted light from a light source (not shown) such as a backlight to be transmitted. The vibration direction is regulated.

[Anisotropic conductive film]
As shown in FIG. 2, an anisotropic conductive film (ACF) 1 is generally formed by forming a conductive particle-containing layer 3 on a release film 2 serving as a base material. As shown in FIG. 1, the anisotropic conductive film 1 has a conductive particle-containing layer 3 interposed between a transparent electrode 17 formed on a transparent substrate 12 of the liquid crystal display panel 10 and an electronic component 18 or a flexible substrate 21. By doing so, the liquid crystal display panel 10 and the electronic component 18 or the flexible substrate 21 are connected and used for electrical connection.

  As the release film 2, a base material such as a polyethylene terephthalate film generally used in anisotropic conductive films can be used.

  The conductive particle-containing layer 3 is formed by dispersing conductive particles 4 in a binder. The binder contains a film-forming resin, a curable resin, a curing agent, a silane coupling agent, and the like, and is the same as the binder used for a normal anisotropic conductive film.

  As the film-forming resin, a resin having an average molecular weight of about 10,000 to 80,000 is preferable. Examples of the film forming resin include various resins such as a phenoxy resin, an epoxy resin, a modified epoxy resin, and a urethane resin. Among these, phenoxy resin is particularly preferable from the viewpoint of film formation state, connection reliability, and the like.

  It does not specifically limit as curable resin, An epoxy resin, an acrylic resin, etc. are mentioned.

  There is no restriction | limiting in particular as an epoxy resin, According to the objective, it can select suitably. As specific examples, for example, naphthalene type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, bisphenol type epoxy resin, stilbene type epoxy resin, triphenolmethane type epoxy resin, phenol aralkyl type epoxy resin, naphthol type epoxy resin, A dicyclopentadiene type epoxy resin, a triphenylmethane type epoxy resin, etc. are mentioned. These may be used alone or in combination of two or more.

  There is no restriction | limiting in particular as an acrylic resin, According to the objective, it can select suitably, For example, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, for example , Trimethylolpropane triacrylate, dimethyloltricyclodecane diacrylate, tetramethylene glycol tetraacrylate, 2-hydroxy-1,3-diaacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane 2,2-bis [4- (acryloxyethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, tris (acryloxyethyl) ) Isocyanurate, urethane acrylate, epoxy acrylate. These may be used alone or in combination of two or more.

  The curing agent is not particularly limited as long as it is a photo-curing type, and can be appropriately selected according to the purpose. However, when the curable resin is an epoxy resin, a cationic curing agent is preferable, and the curable resin is an acrylic resin. In this case, a radical curing agent is preferable.

  There is no restriction | limiting in particular as a cationic hardening | curing agent, According to the objective, it can select suitably, For example, a sulfonium salt, onium salt, etc. can be mentioned, Among these, an aromatic sulfonium salt is preferable. There is no restriction | limiting in particular as a radical type hardening | curing agent, According to the objective, it can select suitably, For example, an organic peroxide can be mentioned.

  Examples of the silane coupling agent include epoxy-based, amino-based, mercapto-sulfide-based, and ureido-based agents. By adding the silane coupling agent, the adhesion at the interface between the organic material and the inorganic material is improved.

  Examples of the conductive particles 4 include any known conductive particles used in anisotropic conductive films. Examples of the conductive particles 4 include particles of various metals and metal alloys such as nickel, iron, copper, aluminum, tin, lead, chromium, cobalt, silver, gold, metal oxide, carbon, graphite, glass, ceramic, Examples thereof include those in which the surface of particles such as plastic is coated with metal, or those in which the surface of these particles is further coated with an insulating thin film. In the case where the surface of the resin particle is coated with metal, examples of the resin particle include epoxy resin, phenol resin, acrylic resin, acrylonitrile / styrene (AS) resin, benzoguanamine resin, divinylbenzene resin, styrene resin, and the like. Can be mentioned.

[Production method]
Next, a manufacturing process of a connection body in which the electronic component 18 and the flexible substrate 21 are connected to the transparent electrode 17 of the transparent substrate 12 through the anisotropic conductive film 1 will be described. First, the anisotropic conductive film 1 is temporarily pressure-bonded onto the transparent electrode 17. The method for temporarily press-bonding the anisotropic conductive film 1 is such that the conductive particle-containing layer 3 is on the transparent electrode 17 side on the transparent electrode 17 of the transparent substrate 12 of the liquid crystal display panel 10. Place.

  And after arrange | positioning the electroconductive particle content layer 3 on the transparent electrode 17, the electroconductive particle content layer 3 is heated and pressurized by the heating press head 30, for example from the peeling film 2 side, and the heating press head 30 is peeled from the peeling film 2. Release the release film 2 from the conductive particle-containing layer 3 on the transparent electrode 17, so that only the conductive particle-containing layer 3 is temporarily pressure-bonded onto the transparent electrode 17. Temporary pressure bonding by the heating and pressing head 30 heats the upper surface of the release film 2 while pressing it against the transparent electrode 17 side with a slight pressure (for example, about 0.1 MPa to 2 MPa). However, the heating temperature is set to a temperature at which a thermosetting resin such as an epoxy resin or an acrylic resin in the anisotropic conductive film 1 is not cured (for example, about 70 to 100 ° C.).

  Next, the electronic component 18 is disposed so that the transparent electrode 17 of the transparent substrate 12 and the electrode terminal of the electronic component 18 face each other with the conductive particle-containing layer 3 interposed therebetween.

  Next, ultraviolet rays are irradiated by the ultraviolet irradiator 31 disposed below the transparent substrate 12, the conductive particle-containing layer 3 is cured, and the electronic component 18 is connected to the transparent substrate 12. At this time, in this connection process, the region where the terminal portion 17a of the transparent electrode 17 and the electronic component 18 are connected is divided into a plurality of connection regions as shown in FIG. Harden by shifting the timing of irradiation start.

  A region where the electrode terminal of the electronic component 18 and the terminal portion 17a of the transparent electrode 17 are connected is appropriately divided into a plurality of connection regions. For example, the electrode terminal of the electronic component 18 and the transparent electrode 17 are connected to each other. When forming a channel, it is divided for each channel. Or the area | region where the electrode terminal of the electronic component 18 and the terminal part 17a of the transparent electrode 17 are connected may divide | segment the whole area | region into a several area | region by an equal area. In FIG. 3, as an example, the electronic component 18 and the terminal portion 17a of the transparent electrode 17 are provided with five first to fifth connection regions CH1 to CH5 that are connected to form a channel. Show. 1st-5th connection area | region CH1-CH5 is substantially equal over the full width of the area | region where the terminal part of the electronic component 18 and the terminal part 17a of the transparent electrode 17 are connected via the anisotropic conductive film 1. FIG. Has been placed.

  The ultraviolet irradiator 31 is provided with first to fifth ultraviolet irradiators 31a to 31e corresponding to, for example, the first to fifth connection regions CH1 to CH5. The ultraviolet irradiator 31 can individually control the irradiation of the ultraviolet irradiators 31a to 31e. In this connection step, the ultraviolet irradiator 31 can be cured by shifting the timing of ultraviolet irradiation for each connection region. In addition, each ultraviolet irradiation part 31a-31e overlaps with an adjacent ultraviolet irradiation part, and an irradiation range overlaps, and it is made not to have the part which is not irradiated with an ultraviolet-ray.

  In this way, by shifting the timing of ultraviolet irradiation, the timing of the start of curing differs for each connection region, and the connection between the electronic component 18 and the transparent substrate 12 is sequentially performed while absorbing distortion due to curing shrinkage in each connection region. Can be planned. This is because the connection start timing is different for each connection region, so that when the connection region first irradiated with ultraviolet rays begins to cure and the binder shrinks and cures, no UV irradiation is applied adjacent to the connection region. In this connection region, since the binder is uncured and has fluidity, the strain due to curing shrinkage in the connection region irradiated with ultraviolet rays can be absorbed by flowing to the connection region side irradiated with ultraviolet rays. It is done.

  Specifically, in the first to fifth connection regions CH1 to CH5 shown in FIG. 3, as shown in FIG. 4A, the irradiation of ultraviolet rays is started from the third ultraviolet irradiation unit 31 c and is positioned at the central portion. It hardens from 3rd connection area | region CH3 to do. Next, after the start of irradiation from the third ultraviolet irradiation unit 31c, after a predetermined time has elapsed, for example, after 1 second, as shown in FIG. 4B, from the adjacent second and fourth ultraviolet irradiation units 31b and 31d. UV irradiation is started, and the second and fourth connection regions CH2 and CH4 are cured. Finally, after the start of irradiation from the second and fourth ultraviolet irradiation units 31b and 31d, after a predetermined time has elapsed, for example, one second later, as shown in FIG. The ultraviolet irradiation from the irradiation parts 31a and 31e is started, and the first and fifth connection regions CH1 and CH5 are cured.

  Thus, according to this connection process, the distortion at the time of hardening of 3rd connection area | region CH3 located in a center part by changing the irradiation timing of the ultraviolet-ray with respect to 1st-5th connection area | region CH1-CH5. The first and fifth connection regions CH1 adjacent to each other are absorbed by the uncured binder in the second and fourth connection regions CH2 and CH4 adjacent to each other, and distortion at the time of curing the second and fourth connection regions CH2 and CH4 is adjacent to each other. , Absorbed with an uncured binder of CH5.

  In contrast, when the first to fifth connection regions CH1 to CH5 are irradiated with ultraviolet rays at the same time, the connection regions CH1 to CH5 start to cure at the same time, so that the distortion of the adjacent connection regions can be absorbed. Can not. Therefore, according to this connection process, it is possible to suppress the distortion of the transparent substrate 12 and to prevent the connection failure of the electronic component 18.

  In addition, when irradiating ultraviolet rays to a connection area that is not adjacent to the connection area that is not irradiated with ultraviolet rays, the distortion due to curing shrinkage of the binder is minimized by irradiating the minimum irradiation amount necessary for ultraviolet curing. Can be suppressed.

  Specifically, in this connection process, the first and fifth connection regions CH1 and CH5 that are finally irradiated with ultraviolet rays are irradiated with the minimum dose necessary for ultraviolet curing, and then all the connection regions CH1 to CH5 are irradiated. UV irradiation may be stopped. For example, as shown in FIG. 4D, the ultraviolet irradiator 31 includes a full ultraviolet irradiator, as shown in FIG. 4 (d), after a predetermined time has elapsed after the start of irradiation from the first and fifth ultraviolet irradiators 31a and 31e. Irradiation from 31a to 31e is stopped.

  As described above, the first and fifth connection regions CH1 and CH5 that are finally irradiated with ultraviolet rays do not have an adjacent region including an uncured binder that absorbs curing shrinkage. By irradiating only the irradiation amount, the distortion accompanying the curing shrinkage of the binder can be minimized.

  In this connection step, it is only necessary to stiffen the timing at which the ultraviolet irradiation is started, and it is not always necessary to align the end of the ultraviolet irradiation in the connection regions CH1 to CH5.

  After the electronic component 18 is connected to the transparent electrode 17 of the transparent substrate 12, so-called FOG (film on glass) mounting is performed in which the flexible substrate 21 is mounted on the transparent electrode 17 of the transparent substrate 12 in the same manner. Thereby, the connection body by which the transparent substrate 12, the electronic component 18, and the flexible substrate 21 were connected via the anisotropic conductive film 1 can be manufactured. Note that these COG mounting and FOG mounting may be performed simultaneously.

  As described above, the COG mounting in which the liquid crystal driving IC is directly mounted on the glass substrate of the liquid crystal display panel and the FOG mounting in which the flexible substrate is directly mounted on the substrate of the liquid crystal display panel have been described as examples. It can be used for other various connections other than the FOG mounting.

[Other timing 1]
Moreover, the area | region which starts ultraviolet irradiation initially may not be one place, and you may start ultraviolet irradiation simultaneously in the several places which are not mutually adjacent | abutted. For example, as shown in FIG. 5A, ultraviolet irradiation may be started from the second and fourth connection regions CH2 and CH4.

  Also in this case, the uncured binder in the connection region adjacent to the connection region irradiated with ultraviolet rays, for example, the first, third, and fifth connection regions CH1, CH3, and CH5 is converted into the second and fourth connection regions CH2, By flowing to CH4, strain in the second and fourth connection regions CH2 and CH4 irradiated with ultraviolet rays can be absorbed. Also in this case, as shown in FIG. 5B, the first, third, and fifth connection regions CH1, CH3, and CH5 are exposed to ultraviolet rays that are not adjacent to the connection region that is not irradiated with ultraviolet rays. In the case of irradiation, the minimum amount of irradiation necessary for ultraviolet curing is irradiated, so that distortion associated with curing shrinkage of the binder can be minimized.

[Other timing 2]
Moreover, in this connection process, you may make it irradiate an ultraviolet-ray from one edge part of the connection area | region divided | segmented into plurality. For example, as shown in FIG. 6 (a), the ultraviolet irradiator 31 starts ultraviolet irradiation from the first ultraviolet irradiation unit 31a to the first connection region CH1, and after a predetermined time has elapsed, for example, after 1 second, The second ultraviolet irradiation unit 31b starts ultraviolet irradiation to the second connection region CH2 (FIG. 6B), and sequentially connects to the fifth connection region CH5 every 1 second. UV irradiation is started (FIG. 6 (c) to FIG. 6 (e)).

  Also in this case, the uncured binder in the connection region adjacent to the connection region irradiated with ultraviolet rays, for example, the second connection region CH2 adjacent to the first connection region CH1, flows to the first connection region CH1. The strain in the first connection region CH1 irradiated with ultraviolet rays can be absorbed. Also in this case, in the case of irradiating the connection region not adjacent to the connection region not irradiated with ultraviolet rays, for example, the connection region CH5 with ultraviolet rays, the minimum irradiation amount necessary for ultraviolet curing is irradiated, so that the binder Distortion accompanying curing shrinkage can be minimized.

[Other timing 3]
Moreover, in this connection process, you may make it irradiate an ultraviolet-ray from the several edge part of the connection area | region divided | segmented into plurality. For example, as shown in FIG. 7A, the ultraviolet irradiator 31 starts the ultraviolet irradiation from the first ultraviolet irradiation unit 31a to the first connection region CH1, and from the fifth ultraviolet irradiation unit 31e to the fifth. UV irradiation to the connection region CH5 is started. After a predetermined time elapses, for example, after 1 second, as shown in FIG. 7B, the second ultraviolet irradiation unit 31b starts to irradiate the second connection region CH2, and the fourth ultraviolet irradiation unit 31d 4 starts to irradiate the connection area CH4 with ultraviolet rays. Further, after a predetermined time has elapsed, for example, after 1 second, as shown in FIG. 7C, ultraviolet irradiation from the third ultraviolet irradiation unit 31c to the third connection region CH3 is started.

  Also in this case, the uncured binder in the connection region adjacent to the connection region irradiated with the ultraviolet light, for example, the second and fourth connection regions CH2 and CH4 adjacent to the first and fifth connection regions CH1 and CH5 is the first. By flowing to the first and fifth connection regions CH1 and CH5, strain in the first and fifth connection regions CH1 and CH5 irradiated with ultraviolet rays can be absorbed. Also in this case, when the ultraviolet rays are irradiated to the third connection region CH3 that is not adjacent to the connection region not irradiated with the ultraviolet rays, the binder is cured by irradiating with the minimum irradiation amount necessary for ultraviolet curing. Distortion accompanying shrinkage can be minimized.

[Other timing 4]
In the above description, the region where the terminal portion 17a of the transparent electrode 17 and the electronic component 18 are connected is divided into connection regions arranged in a line. However, as shown in FIG. It may be divided into regions. Also in this case, the curing shrinkage of the binder can be achieved by stiffening the UV irradiation start timing for each connection region, such as from the center to the end, from the end to the end, or from multiple ends to the center. Can be absorbed.

  In the above description, an ultraviolet curable binder is used. However, the present invention may use light other than ultraviolet light as long as the binder can be cured by irradiation. Moreover, although the anisotropic conductive film 1 which has a film shape as an electroconductive adhesive was demonstrated above, even if it is a paste form, there is no problem. In the present application, a film-like conductive adhesive film such as the anisotropic conductive film 1 containing the conductive particles 4 or a paste-like conductive adhesive paste is defined as “adhesive”.

  Next, examples of the present invention will be described. In the present embodiment, a connection body provided with first to fifth connection regions CH1 to CH5 constituting five channels by connecting a transparent electrode provided on a glass substrate and an electrode terminal provided on an IC chip. By forming a sample (see FIG. 3), for each connected body sample, the connection state between the IC chip and the substrate is evaluated by the conduction resistance value (Ω), and the display unevenness is measured by the amount of warpage (μm) of the substrate. Substitute evaluation.

The anisotropic conductive film used for connection is composed of an adhesive layer composed of a conductive particle-containing layer (ACF layer) having a thickness of 18 μm. The ACF layer is
Phenoxy resin (YP-70: manufactured by Nippon Steel Chemical Co., Ltd.); 20 parts by mass liquid epoxy resin (EP-828: manufactured by Mitsubishi Chemical Corporation); 30 parts by mass solid epoxy resin (YD014 :) Nippon Steel Chemical Co., Ltd. 20 parts by mass conductive particles; (AUL 704: manufactured by Sekisui Chemical Co., Ltd.): 30 parts by mass cationic curing agent (LW-S1: manufactured by San Apro Co., Ltd.); The mixed solution was applied onto a PET film, dried in an oven, and formed into a film.

  This ACF was adjusted to have a thickness of 18 μm and laminated and laminated to obtain an anisotropic conductive film. The anisotropic conductive film used for an Example and a comparative example is width 4.0mm x length 40.0mm.

As an evaluation element,
External shape: 1.8mm x 34.0mm
Thickness: 0.5mm
Thus, an evaluation IC in which a continuity measurement wiring was formed was used.

  As an evaluation base material to which the evaluation IC is connected, a glass substrate having a glass thickness of 0.5 mm and having a continuity measurement wiring formed thereon was used.

  An evaluation IC was placed on the glass substrate through the anisotropic conductive film, and connected by thermal pressing with a heating press head and ultraviolet irradiation to form a connected body sample. The heat-pressing surface of the heating and pressing head is 10.0 mm × 40.0 mm, and the heat-pressing surface of the heating and pressing head is processed with a fluororesin having a thickness of 0.05 mm as a buffer material. The temperature conditions of the heating and pressing head are all 110 ° C., and the pressing conditions are 70 MPa and 5 seconds.

  The ultraviolet irradiation is performed 5 seconds after the start of the thermal pressing of the evaluation IC by the heating and pressing head set to a predetermined temperature, and the irradiation is performed after a predetermined time has elapsed from the start of the thermal pressing for each connection region. Then, the irradiation was uniformly stopped after 5 seconds from the start of the heat press with the heating press head. Table 1 shows the elapsed time from the start of thermal pressing of the evaluation IC by the heating and pressing head to the irradiation of ultraviolet rays to the connection regions CH1 to CH5 according to the examples and comparative examples.

  In Example 1, the elapsed time until the third connection region CH3 is irradiated with ultraviolet rays is set to 0 second, and the first, second, fourth, and fifth connection regions CH1, CH2, CH4, and CH5 are irradiated with ultraviolet rays. The elapsed time of each was 1 second. That is, in Example 1, the ultraviolet irradiation time of the third connection region CH3 is 5 seconds, and the ultraviolet irradiation time of the first, second, fourth, and fifth connection regions CH1, CH2, CH4, and CH5 is 4 seconds. is there.

  In Example 2, the elapsed time until the ultraviolet irradiation to the third to fifth connection regions CH3 to CH5 is set to 1 second, the elapsed time to the ultraviolet irradiation to the second connection region CH2 is set to 2 seconds, and the first The elapsed time until the ultraviolet irradiation of the connection region CH1 was 3 seconds. That is, in Example 2, the ultraviolet irradiation time of the third to fifth connection regions CH3 to CH5 is 4 seconds, the ultraviolet irradiation time of the second connection region CH2 is 3 seconds, and the ultraviolet irradiation time of the first connection region CH1. Is 2 seconds.

  In Example 3, the elapsed time until the third connection region CH3 is irradiated with ultraviolet light is 1 second, the elapsed time until the second and fourth connection regions CH2 and CH4 are irradiated with ultraviolet light is 2 seconds, The elapsed time until the ultraviolet irradiation to the fifth connection regions CH1 and CH5 was 3 seconds. That is, in Example 3, the ultraviolet irradiation time of the third connection region CH3 is 4 seconds, the ultraviolet irradiation time of the second and fourth connection regions CH2 and CH4 is 3 seconds, and the first and fifth The ultraviolet irradiation time of the connection regions CH1 and CH5 is 2 seconds.

  In Example 4, the elapsed time until the first and fifth connection regions CH1 and CH5 are irradiated with ultraviolet light is 1 second, and the elapsed time until the second and fourth connection regions CH2 and CH4 are irradiated with ultraviolet light is 3 seconds. Seconds, and the elapsed time until the third connection region CH3 was irradiated with ultraviolet rays was 4 seconds. That is, in Example 4, the ultraviolet irradiation time of the first and fifth connection regions CH1 and CH5 is 4 seconds, the ultraviolet irradiation time of the second and fourth connection regions CH2 and CH4 is 2 seconds, The UV irradiation time of the third connection region CH3 is 1 second.

  In Comparative Example 1, the elapsed time until ultraviolet irradiation to the first to fifth connection regions CH1 to CH5 was uniformly set to 0 seconds. That is, in Comparative Example 1, the ultraviolet irradiation time of the first to fifth connection regions CH1 to CH5 is uniformly 5 seconds.

  In Comparative Example 2, the elapsed time until the ultraviolet irradiation to the first to fifth connection regions CH1 to CH5 was uniformly 4 seconds. That is, in Comparative Example 2, the ultraviolet irradiation time of the first to fifth connection regions CH1 to CH5 is uniformly 1 second.

In addition, it shows in Table 2 about the relationship between ultraviolet irradiation time and the cure shrinkage rate of the anisotropic conductive film which concerns on an Example and a comparative example. Curing shrinkage refers to the rate at which the anisotropic conductive film shrinks with ultraviolet curing,
Curing shrinkage rate = (cured material specific gravity of adhesive layer−resin liquid specific gravity of adhesive layer) / cured material specific gravity of adhesive layer × 100
Can be obtained.

  Under the above conditions, heat pressing and ultraviolet irradiation are performed to form a connected body sample in which the IC for evaluation is connected to the glass substrate. For each sample, the size of the warp (μm) and the conduction resistance value (Ω) are set. It was measured.

  As shown in FIG. 9, the warp measurement method is performed by scanning the stylus 41 from the lower surface of the glass substrate 40 of the joined body sample using a stylus type surface roughness meter (SE-3H: manufactured by Kosaka Laboratory Ltd.). Then, the warpage amount (μm) of the glass substrate surface after connection of the evaluation IC was measured.

  For the measurement of the conduction resistance value, after performing a high temperature and high humidity test in which the connected body sample is left in an environment of 85 ° C. and 85% RH for 500 hours, it is connected to the bumps 42 of the evaluation IC as shown in FIG. An ammeter A and a voltmeter V were connected to the metal wiring 43 of the glass substrate 40, and a conduction resistance value was measured when a current of 1 mA was passed by a so-called four-terminal method. The results are shown in Table 2.

  As shown in Table 2, in each embodiment, the curing is performed by shifting the irradiation timing of ultraviolet rays over the first to fifth connection regions CH1 to CH5, so that the connection region where ultraviolet irradiation is performed in advance is cured. The distortion in the resin is absorbed by the uncured binder in the adjacent connection region. Therefore, according to each Example, the warpage amount was within 11.3 μm at the maximum, and the connection resistance was 12.4Ω at the maximum. Therefore, according to this connection process, it turns out that the distortion of a glass substrate can be suppressed and the connection failure of evaluation IC can be prevented.

  On the other hand, in Comparative Example 1 in which the first to fifth connection regions CH1 to CH5 are irradiated with ultraviolet rays simultaneously with heat pressurization, the respective connection regions CH1 to CH5 start to be cured simultaneously, and the ultraviolet rays are irradiated. Since the time was long and the cure shrinkage ratio was as large as 2.7%, it was not possible to absorb the distortion of the adjacent connection region, the warpage amount was as large as 14.5 μm, and the connection resistance was 15.1Ω.

  Further, in Comparative Example 2 in which irradiation of ultraviolet rays was started after the elapse of 4 seconds from the thermal pressurization to the first to fifth connection regions CH1 to CH5, the warping was 5. Although it was suppressed to 0 μm, the curing was insufficient, and the connection resistance after the high temperature and high humidity test was 110.8Ω.

  In each example, the irradiation is started from the third connection region CH3 at the center, and the ultraviolet rays are sequentially irradiated toward the end portion, and from the connection regions CH1 and CH5 at the end portion to the center portion. In Example 4 where ultraviolet rays were irradiated toward the surface, the amount of warpage and connection resistance were relatively good. This is because a connection region that is not irradiated with ultraviolet rays is always provided in a connection region that is irradiated with ultraviolet rays. It is thought that it was possible to continue.

  In particular, in Example 3, the irradiation of ultraviolet rays to the connection regions CH1 and CH5 at the end is the last, the irradiation time is short, and the curing shrinkage rate is low. Since the warpage of the glass substrate increases from the central portion toward the outer side, Example 3 in which the outer side (end portion) curing shrinkage rate is low was able to suppress the warp most.

DESCRIPTION OF SYMBOLS 1 Anisotropic conductive film, 2 Release film, 3 Conductive particle content layer, 4 Conductive particle, 10 Liquid crystal display panel, 11 Transparent substrate, 12 Transparent substrate, 13 Seal, 14 Liquid crystal, 15 Panel display part, 16 Transparent electrode , 17 Transparent electrode, 17a terminal part, 18 electronic component, 20 COG mounting part, 21 flexible substrate, 22 FOG mounting part, 24 alignment film, 25 polarizing plate, 26 polarizing plate, 30 heating press head, 31 UV irradiator

Claims (9)

A step of placing electronic components on the substrate via a photo-curing adhesive;
The adhesive has a step of irradiating and curing light from a plurality of light sources ,
An area where the substrate and the electronic component are connected is divided into a plurality of connection areas,
The connection areas divided into a plurality are arranged in parallel so as to be adjacent to each other,
For each of the connection regions, the corresponding light source is individually controlled for irradiation, and the curing is performed by shifting the timing of the light irradiation start.
A method for manufacturing a connection body in which the electronic component is connected to the substrate. Start irradiation of the light from any one or more of the connection areas divided into a plurality,
The manufacturing method of the connection body of Claim 1 which starts irradiation of the said light to connection areas other than the said arbitrary one or some connection area after progress for predetermined time.   The method for manufacturing a connected body according to claim 2, wherein light irradiation to all the connection regions is stopped after the connection region to which the light is finally irradiated is irradiated with a minimum irradiation amount necessary for photocuring. The irradiation of the light is started from the central connection region of the region where the substrate and the electronic component are connected among the connection regions divided into a plurality of regions,
The manufacturing method of the connection body of Claim 2 or Claim 3 which starts irradiation of the said light to connection areas other than the said center connection area after predetermined time progress.   The manufacturing of the connection body according to claim 4, wherein the timing of starting the irradiation of the light stepwise from the central connection region toward the connection region at the end of the region where the substrate and the electronic component are connected is delayed. Method. Start irradiation of the light from the connection region at one or more ends of the region where the substrate and the electronic component are connected,
The manufacturing method of the connection body of Claim 2 or Claim 3 which starts irradiation of the said light to connection areas other than the connection area | region of the said one or some edge part after predetermined time progress. Start irradiation of the light from the connection region at one end of the region where the substrate and the electronic component are connected,
The manufacturing method of the connection body of Claim 6 which delays the timing which starts irradiation of the said light in steps toward the said connection area | region of the other edge part of the area | region where the said board | substrate and the said electronic component are connected. The irradiation of the light is started from the connection region at a plurality of ends of the region where the substrate and the electronic component are connected,
The manufacturing method of the connection body of Claim 6 which delays the timing which starts irradiation of the said light stepwise toward the said connection area | region of the center of the area | region where the said board | substrate and the said electronic component are connected. A step of placing electronic components on the substrate via a photo-curing adhesive;
The adhesive has a step of irradiating and curing light from a plurality of light sources ,
An area where the substrate and the electronic component are connected is divided into a plurality of connection areas,
The connection areas divided into a plurality are arranged in parallel so as to be adjacent to each other,
An electronic component connection method for connecting the electronic component on the substrate, wherein the corresponding light source is individually controlled for each connection region and is cured by shifting the timing of the light irradiation start.